Monolithic vs Microservice Architecture: Which is right for you?

In considering the ideal structure for your app, you can opt for a more traditional monolithic architecture or choose to build a microservices application. There are ultimately benefits and considerations to each type of software architecture, with the decision depending largely on your app’s ideal functionality, the structure of your development teams, and your business goals.

In this blog, we’ll look at the advantages of each type of software architecture, as well as various use cases and how you can migrate to a microservices architecture as your development team looks to scale. 

What is a monolithic architecture?

Since the early days of mobile app development, software engineers have built apps in a monolithic architecture. This process brought the frontend and backend code—and their subsequent teams—together in a single tier application. It combined UI, business logic, and data access into a single unit.

In short, monolithic architecture is a self-contained, unified unit that functions independently from other applications. In monolithic applications, all services act based on their own logic, with a database and specific functions behind them. In short, it’s a singular, often very large and cumbersome system using a single codebase that merges disparate functionality and needs together. This application requires updating and deploying the entire thing to release updates.

While it may work well for small teams, a monolithic approach comes with its own set of challenges. As teams consider scalability, working together in unison, shipping quickly, and responding to customer requests becomes difficult if all teams are working in a single tier structure.

What is a microservice architecture?

Microservices, also called microservice architecture, structure applications as a collection of services that are independently deployable yet still loosely related. These services are also organized around specific business capabilities, and are typically owned by a small team.

One of the major advantages of microservice architecture is that it enables development teams to deliver large, complex applications more rapidly and frequently.

Monolithic architecture makes sense for you if...

If your app is in its infancy, a monolithic approach may make sense. It can be convenient at the outset of a project because it’s easy to manage the codebase and deploy the application. With a monolith, everything can be released at once. This can be particularly helpful for startups or small teams.

If you want to manage everything from a single codebase, monolithic architecture makes sense as well. The application would be built and shipped from a single codebase, with one executable bundle or directory needed for deployment.

Since monolithic applications are centralized, end to end testing can often be performed faster than with a more distributed application. Monolithic apps can also make debugging simpler, since teams only need to comb through a single codebase as opposed to multiple.

Disadvantages of monolithic applications

Monoliths are often slower to build and ship, since everything is coming from one codebase. That also means your team is bound to the technology and programming language decided at the outset of the project, or you risk having to redo a lot of work.

Scalability is a major challenge for monolithic applications, since individual components can’t be scaled. Reliability is as well, as errors in any particular module risk affecting the whole application. This sort of tight coupling is a major drawback for teams who want to ship faster.

Lastly, deployment can be hindered since these types of applications require redeployment of the entire monolith–something that requires a great deal of coordination amongst all parties involved.

Microservice architecture makes sense for you if...

If you feel that your application has outgrown a monolithic architecture, it may make sense to explore new technologies such as microservices. As applications grow in their complexity and digital footprint, it may make sense to move to an architecture that emphasizes separate lanes while maintaining loose coupling.

If you’re concerned with increasing development speed, then microservices may make sense. Monolithic applications are typically slower to develop.

If scalability is a concern, particularly for individual components of an application, then microservices are a good option. One of the benefits of microservices is that they promote more agile ways of working, with small teams focused on deploying more frequently. This also means new instances of various services can be spun up as others reach capacity, allowing for flexibility and scaling.

Microservices also allow for more agile development, since a monolith is limited to the technologies already within it. Microservices, on the other hand, are a more distributed system, so different frameworks, technologies, and collections of dependencies can be leveraged within the entire application. Teams can also quickly roll back features or updates that don’t work, which helps improve time-to-market as well as keeping the development process flexible.

If you’re looking to adopt a DevOps structure within your team, microservices go hand in hand. Both are focused on continuous delivery and iteration within parts of the application.

Disadvantages of microservices

Whereas a monolithic application stems from a single codebase, microservices rely on a much more distributed system. That means they can get far more complicated (and fast), especially as new features and updates are pushed by multiple teams in parallel.

This all leads to additional organizational challenges, as teams need to focus on communicating effectively to ensure a cohesive final product.

Since microservice applications have their own codebases, that can make debugging a challenge. With a lack of standardization, multiple programming languages, and multiple people signing and shipping code, sometimes via workflow automation,  it can be difficult to debug and maintain the application.

Migrating from a monolithic application to microservice architecture

If you think microservices are for you, then it may be time to migrate your application. Many projects begin as monoliths and are migrated to microservices, so rest assured that a smooth migration is possible.

First, understand that migration to a microservices approach requires a culture shift as much as a technical process. Teams will need to learn to work in more self-contained ways, focused on subsets of the overall user experience and independent deployment while still keeping the entire system in mind.

Next, determine the sequence of how you plan to migrate - noting that different customers will have different data within your application and will likely use the microservices within your new application in different ways. Having a plan is key, and you’ll want to ensure that plan has the proper support and project management behind it.

Then, decide on the proper tools for migrating. Whether you choose to build tooling internally or seek outside assistance, the right tools can help ensure that your team is on the same page and that your customers (and their data) are migrated over smoothly.

Lastly, once you’ve identified the proper plan of action, tools, and have your team on board - you’re ready to start migrating. Understand that it may be a slow process with possible bumps in the road, but in the end, your team will be able to create better apps faster.

If you’re looking to learn more, we do a deeper dive into the benefits of microservices in this article.